I run up against a more contemporary version of this just a out every day in my own writing as I work hard to increase public consciousness of ongoing injustices against LGBTQ people.

I often call out religious leaders who teach outrageous things about the moral depravity of members of gender and sexual minorities. I recently called out Earl Fernandes, a virulently homophobic priest Pope Francis just promoted to Bishop of Columbus. He advocates disgusting things, like gay men cannot truly love their partners, that people become gay because of relationships with their parents as children, that conversion therapy can work sometimes if you pray hard enough. That a woman's essential destiny is motherhood.

Most people in the United States understand Fernandes's beliefs and teachings are evil and ignorant, but they oppose calling him out as evil and ignorant.

His beliefs are his, many people tell me, and they should be respected because they're sincere beliefs. Don't say mean (meaning true) things about him. Don't disrespect his religion.

That's the exact same kind of moral relativism you were talking about. And it just won't go away. People just can't seem to wrap their heads around agreeing that mistreating members of marginalized minorities is evil.